Snakes declining at alarming rate, say scientists

Scientists say the rate of decline in snakes is ‘alarming’. The grass snake, Natrix natrix, is stable in the UK and France. Photograph: Solvin Zankl/Getty Images

The widespread disappearance of snakes will be one impact of climate change that some people may find it hard to regret. But as vital predators in sensitive habitats such as rice fields, their decline will have wider ecological consequence, say scientists.

The first major study of the problem, published today, will also be seen as another powerful sign of the worldwide destruction of the natural world, which is causing growing concern about the loss of vital services from rainfall to medicines.

Scientists in five countries across three continents report they found “alarming” declines in snake numbers after monitoring 17 populations in a variety of habitats – something they believe could be part of a global phenomenon.

The paper reports 11 of the population groups “declined sharply”, while five remained stable, and one showed a very weak sign of increase. Many of the researchers in the UK, France, Italy, Nigeria and Australia also found evidence of “population crashes” – a sudden decline followed by no sign of recovery – a trend which would make the survivors more vulnerable to being wiped out by further pressures.

“All the declines occurred during the same relatively short period of time and over a wide geographical area that included temperate, Mediterranean and tropical climates,” write the authors. “We suggest that, for these reasons alone, there is likely to be a common cause at the root of the declines and that this indicates a more widespread phenomenon.”

Although the paper stresses there is no proof of the cause of the losses, the researchers say they “suspect” loss or deterioration of habitats and declining prey are among the main problems faced by snake populations. They believe that all the immediate threats have climate change as a common cause.

“The main importance of these findings is that snakes are top predator within the habitats they are found in and as such play a potentially important role in the functioning of many ecosystems,” said Chris Reading of the UK’s Centre for Ecology and Hydrology, who led the research. “For example they play an important role in pest control – small rodents [like] rats and mice – in areas such as paddies and sugar cane plantations.”